Field of the Invention
The present invention relates to a handheld device and a frequency tracking method thereof. More particularly, the handheld device of the present invention triggers modem module to execute a frequency compensation process according to a heat source temperature to reduce the impact of oscillator frequency offset caused by a heat source.
Descriptions of the Related Art
With the development of communication technologies, the wireless handheld device has been widely used in people's daily life. To meet the compact design of the handheld device, it is hard to avoid disposing the oscillator close to the baseband (BB) processor which is a critical heat source of the handheld device.
Since the frequency of the oscillator is sensitive to the change in temperature, the large change in temperature (e.g., when BB processor becomes busy or turned-off) may cause large frequency offset in the oscillator. The frequency offset is accumulated until the Modem wakes up to receive the signal from the paging channel. However, the current frequency tracking mechanism which only uses the periodic signal received from the paging channel is unable to deal with large frequency offset, and consequently the related modem channel reception may fail.
Accordingly, an urgent need exists in the art to deal with large frequency offset caused by the large change in temperature around the oscillator so as to prevent the failure of related modem channel reception due to large frequency offset.